This complicated knot of legal interpretation may make it difficult for members of the committee majority and minority to bounce a clean ricochet off Mueller.

Democrats: What didn't you investigate?

Mueller has stepped down and his work is over. But Democrats are anxious about trying to preserve some momentum to animate their own ongoing investigations into Trump.

The president and his supporters have pointed to Mueller's findings and called them the final word on any alleged impropriety. Trump has said, for example, that he assumes Mueller obtained his tax returns and concluded nothing was wrong.

Now Democrats will have the ability to ask Mueller whether that's true. The answer could have some of the biggest long-term political implications for House Speaker Nancy Pelosi, D-Calif., and her majority.

If Mueller says — in so many words — that his report is a clean bill of health for Trump, it will mean new headwinds for Democrats' investigations and strengthen opponents' criticism that they're just new fishing expeditions.

If Mueller appears to clear the way for the judiciary, intelligence and other committees to press ahead with the work they've begun, Democrats would be happy to take the torch from him.

But remember, the Justice Department has made it clear that Mueller should not discuss aspects of the investigation that have been redacted and not cleared for public consumption.

Republicans: Who are you to "exonerate" anyone?

Trump, White House aides and their supporters in Congress argue that Mueller has violated the most basic responsibility of a prosecutor: assess whether there's sufficient evidence of lawbreaking and, if so, seek an indictment.

If not, don't.

It isn't a prosecutor's job to write a report about findings short of charges and it isn't his role to "clear" anyone, Mueller's critics argue. Everyone is supposed to be cleared in the American system unless she or he is proved guilty.

Yet Mueller wrote this: "While this report does not conclude that the president committed a crime, it also does not exonerate him."

So not only have White House attorneys faulted Mueller for his report — "part 'truth commission' report and part law school exam paper," as lawyer Emmet Flood scoffed — members of Congress likely want to ask Mueller why he went so far afield of what they consider his remit.

Democrats: Will you say now whether you'd indict Trump?

Look for majority Democrats to take the opposite tack.

Barr, the attorney general, has said he considered the way clear for Mueller to say whether he believed Trump merits criminal charges in connection with the alleged obstruction of justice — with the caveat that there could be no actual indictment.

All right, Nadler and his colleagues may say to Mueller, not only are you off the Justice Department payroll, your own former boss has said he didn't object to your giving an opinion about this. Even though the Justice Department's policy kept you from charging Trump, would you if you could have?

Or to put it a different way, would anyone else who has done the things you've found Trump has done face criminal charges?

Republicans: Why did you remove Peter Strzok?

The melodrama involving Strzok, formerly a top FBI counterintelligence specialist, and Lisa Page, formerly a top FBI lawyer, has been one of the most embarrassing subplots in the Russia imbroglio for the FBI.

Strzok and Page exchanged a number of candidly political text messages on their government phones in 2016 at the time they were involved in an extramarital affair.

When investigators discovered all this and publicized the story and their messages, it fueled criticism that the Russia investigation was the product of "bias" by an insider cabal out to get Trump.

Mueller removed Strzok from the special counsel's office when he got word about the text messages. Expect Republicans to invite him to relate that story early and often — and to press him about why they should accept anything from an office that included Strzok and others who've been criticized for political "bias."

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